iFrame and in screen window

Have a custom WAB app with a popup that provides a link for user to click on. This link brings them to a Survey123 form. Instead of opening up a new browser tab, I'm considering using the iFrame option to display the form in window.

A note too my previous question. If I said that my WAB app is run on my own server but hosted on AGOL for the services and requires login. Does that change your viewpoint on iFrames? The users will be internal